1. Field
The present disclosure relates generally to an apparatus and a method for displaying an image, and an apparatus and a method for driving a light emitting device. More particularly, the present disclosure relates to such an apparatus and method which saves manufacturing costs and reduces generation of heat when the light emitting device is used in an image displaying apparatus, for example, as an LED backlight.
2. Description of the Related Art
In general, an image display device used to display an image signal input from a video card can be classified into a light emitting type and a light receiving type. For example, an image display device such as a CRT or PDP is a light emitting type and displays an image by emitting the light by itself, whereas an LCD selectively generates contrast and displays the image by injecting a liquid crystal between two thin glass substrates and changing arrangement of liquid crystal molecules when power is supplied. Since, an LCD is of the light receiving type, it cannot operate without a rear light source. Accordingly, a surface light source backlight lamp is required to maintain uniform brightness throughout the screen.
The backlight lamp can be implemented, for example, by a plurality of LEDs disposed around edges of a panel or over a rear side of the panel in order to provide light as the surface light source. Typically, the type placed around the edges is referred to as an edge type, and the type placed over the rear side is referred to as a direct type.
The image display device includes a lamp driver for driving the backlight lamp. The lamp driver can include a power circuit for switching the backlight lamp on and off.
However, LED devices forming the backlight lamp are sensitive to temperature. To accommodate the heat generated inside the LED device and the driver, various conventional methods relating to the lamp driver are known. For example, one conventional technique configures an LED driving circuit on the secondary side of a transformer and controls the heat by sensing the temperature through a temperature sensor. Such a technique is subject to low accuracy and suffers from a high rate of defective products relating to the assembly of the sensor.